Improvement in rock-drills



c. s. PATTlsN..

Rock-Drills.

Patentedv Nov. 24, 1874'.

In ifemvr. y

Wz'wesses,

UNITED STATES vPATENT OFFICE.

CHARLES S. PATTISON, OF ASTORIA, NEW YORK.

IMPROVEMENT IN ROCK-DRILLS.

Specification forming part of Letters Patent No. 157,133, dated November24, 1874; application filed September 8, 1874.

To all whom it may concern:

Beit known that I, CHARLES S. PATTIsoN, of Astoria, in the county ofQueens and State of New York, have invented an Improvement inRock-Drills; and I do hereby declare that the following, taken inconnection with the drawings which accompany and form part of thisspecification, is a description of my invention sufficient to enablethose skilled in the art to practice it.

This improvement is designed to avoid lost motion usually consequentupon the wear ot the thread ofthe feed-nut and screw, or, in otherwords, to use the motion that would otherwise be lost; and it consistsin making the feed-nut in two parts, and with threads of differentpitch, such that when its larger or main thread, or the thread upon thescrew, becomes in any degree worn away by use, it may be turned andtightened by means of its liner thread, thus drawing the two parts-ofthe nut together, or separating them wider apart, and meeting the lossby wear. y

In the drawing, A is the main screw, and B D my improved feed-nut,formed in two parts, as shown, each part having a thread, b,corresponding to that of the screw A, this thread b of the part Bextending through a portion of its length, and the remainder of thispart B having a bore ofV larger diameter, in which is made a finerthread, c, corresponding with the 'thread d on the exterior of the partD, which extends through the head of the cylinder, the cylinder and nutbeing shown in longitudinal section, the better to display theconstruction of the parts constituting my improvement. e f arelock-nuts, serving to hold D firmly to place.

This construction of the nut B D, with its coarser and finer threads,the coarser thread engaging with A, and the finer thread serving to adjust the parts B D to each other, enables the nut, when the largerthreads have been worn away so as to work loosely, to be tightened up byscrewing nearer to or farther from each other, by means of the thread 0,until the lost motion is taken up.

A space, h, is purposely left between the portion B of the nut and thelock-nut g sufficient to allow for all the lost motion that is possiblefrom this wear; and this lock-nut g, when the lost motion has been takenup, may be screwed up against B to hold it firmly to place; and myconstruction permits the satisfactory use of my improved divided nut,with its capacity for taking up and using the lost motion, until thethread upon it or upon screwA is entirely gone.

Instead of the threads of different pitch, the same result may beaccomplished by putting in threads of the same pitch, the one being aright-hand and the other a left-hand thread.

-It is found from experience that nuts made as above described are farmore durable than when made as heretofore, lasting more than twice aslong.

I claim- The feed-nut made in two parts, B D, each engaging with thethread ofthe screw A, and also engaging with each other by means of afiner thread, c d, and operating in the man'- ner and for the purposedescribed.

Executed this 8th day of August, A. D. 1874.

CHARLES S. PATTISON.

Witnesses:

EDWD. M. WHITNEY, THEO. V. AYEEs.

